Xibin Yu

Synthesis and luminescence of Sr2CeO4 superfine particles by citrate-gel method

Abstract A strong blue-white emission phosphor Sr 2 CeO 4 superfine particles, containing SrCe 4 O 7 , have been synthesized using a citrate-gel method. The crystalline phase and luminescence properties of superfine particles are reported. The results show that the strong blue-white emission is assigned to Ce 4+ –O 2− charge-transfer transition (CTT) of Sr 2 CeO 4 and is not related to a lattice defect. The emission spectrum of post-heat-treated particles exhibits a broad band maximum at 470 nm, and the emission intensity is not affected by the existence of SeCe 4 O 7 .

New Eu-doped phosphor prepared by sol–gel process

Abstract Eu-doped silica gel modified with K + and Sr 2+ ions was obtained by sol–gel process. The complex gel annealed at 873 K was characterized with TEM, XRD, PL, etc. Results showed that the gel desolventized around 393 K and polymerized to create complex silicate around 833 K while heating. It presented steadily intense luminescence because of part of doped europium reduction spontaneously. We found that the modified on silica gel doped with europium lowered the luminescent transfer temperature about 500 K.

Preparation of hexagonal cerium oxide nanoflakes by a surfactant-free route and its optical property

Hexagonal cerium oxide nanoflakes have been synthesized by using a surfactant-free route. Transmission electcron microscopy (TEM), x-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric and differential thermal analysis (TG-DTA), Brunauer–Emmett–Teller adsorption isotherm (BET), photoluminescence (PL), and ultraviolet–visible (UV–VIS) were used to characterize the sample. The mean size of the nanoflakes is about 30 nm and the specific surface is about 70.08 m2·g−1 when annealed at 400 °C. The acidity and superfluous NH4NO3 play a key role on the formation of nanoflakes in which there exists Ce (IV) and very little Ce (III). The nanoflakes exhibit a wide PL emission peak among 350–400 nm, strong absorption ranged from 200–450 nm, and strong reflection in the visible region. As the sizes of as-prepared samples decrease, a clear blue shift in the absorbing edge is observed. The linear relationship between ΔEg and D is shown in a log–log plot. The as-prepared cerium oxide nanoflakes can be widely used as UV absorbent and polishing materials.